/*
 * Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.sql;

import java.sql.*;

/**
 * The facility that a disconnected <code>RowSet</code> object calls on
 * to populate itself with rows of data. A reader (an object implementing the
 * <code>RowSetReader</code> interface) may be registered with
 * a <code>RowSet</code> object that supports the reader/writer paradigm.
 * When the <code>RowSet</code> object's <code>execute</code> method is
 * called, it in turn calls the reader's <code>readData</code> method.
 *
 * @since 1.4
 */

public interface RowSetReader {

    /**
     * Reads the new contents of the calling <code>RowSet</code> object.
     * In order to call this method, a <code>RowSet</code>
     * object must have implemented the <code>RowSetInternal</code> interface
     * and registered this <code>RowSetReader</code> object as its reader.
     * The <code>readData</code>  method is invoked internally
     * by the <code>RowSet.execute</code> method for rowsets that support the
     * reader/writer paradigm.
     *
     * <P>The <code>readData</code> method adds rows to the caller.
     * It can be implemented in a wide variety of ways and can even
     * populate the caller with rows from a nonrelational data source.
     * In general, a reader may invoke any of the rowset's methods,
     * with one exception. Calling the method <code>execute</code> will
     * cause an <code>SQLException</code> to be thrown
     * because <code>execute</code> may not be called recursively.  Also,
     * when a reader invokes <code>RowSet</code> methods, no listeners
     * are notified; that is, no <code>RowSetEvent</code> objects are
     * generated and no <code>RowSetListener</code> methods are invoked.
     * This is true because listeners are already being notified by the method
     * <code>execute</code>.
     *
     * @param caller the <code>RowSet</code> object (1) that has implemented the
     *         <code>RowSetInternal</code> interface, (2) with which this reader is
     *        registered, and (3) whose <code>execute</code> method called this reader
     * @exception SQLException if a database access error occurs or this method
     *            invokes the <code>RowSet.execute</code> method
     */
    void readData(RowSetInternal caller) throws SQLException;

}
